Successive non-radical and radical process of peroxymonosulfate-based oxidation using various activation methods for...

To enhance the mineralization of toxic organic pollutants is crucial for the alleviation of environmental pollution. In this study, the successive non-radicals and radicals process (SNRP) of peroxymonosulfate (PMS)-based oxidation was performed using various methods for PMS activation, including UV, ozone, gamma radiation and biochar and applied for enhancing the mineralization of sulfamethoxazole (SMX). The results showed that SNRP-UV could improve the mineralization of SMX, and both SNRP-UV and PMS/UV could completely mineralize SMX. For SNRP-Ozone, SNRP-Radiation and SNRP-Biochar, compared to the sole radical oxidation, all SNRPs could enhance the mineralization of SMX. The biochar-induced SNRP obtained the maximum mineralization increment, followed by gamma irradiation-induced SNRP and ozone-induced SNRP. Sulfate radicals were mainly responsible for SMX mineralization for SNRP-Biochar, while hydroxyl radicals for SNRP-Radiation, and the synergetic effect of ozone and sulfate radicals for SNRP-Ozone. Different degradation intermediate products were identified in different SNRP, further revealing that SNRP induced by different methods had different mineralization capacity. This study further demonstrated that SNRP could be a new strategy for enhancing the mineralization of SMX.